1. Field of the Invention
This invention relates to a camera having an AE lock function.
2. Description of the Related Art
It has been known in the art to provide cameras with an AE lock function. The camera of this kind is switched from the normal to the AE lock mode when a subject of principal photographic interest is put out of the center of the view field, so that a proper exposure is made to the subject. That is, as the central spot metering operates, the photographer first aligns the camera to the subject in order to measure its brightness and after the measured value of brightness is memorized, then changes the composition to a desired one with the subject out of the center of the view field before a shot is taken. Because the exposure is controlled in accordance with the memorized brightness, it is insured that a proper result for the subject is attained.
However, in photographic situations where the intensity of ambient light with which the subject was illuminated was rapidly changing, a problem arose that when the conventional camera was in AE lock mode, it was impossible to insure that the proper exposure was made to the subject because its brightness changed just before shooting. For example, a series of patches of clouds were moving at a fast speed across the sun, when the AE lock photography was performed. Under such a condition, there was produced a large difference between the brightnesses of the subject at the time of AE lock and, after the later readjustment of the composition, at the time of the shot, so that a large percentage of photographs taken were found to be unacceptable.